1. Field of the Invention
Generally, the present disclosure relates to the manufacture of semiconductor devices, and, more specifically, to an electronic fuse having a substantially uniform thermal profile.
2. Description of the Related Art
In modern integrated circuits, a very high number of individual circuit elements, such as field effect transistors in the form of CMOS, NMOS, PMOS elements, resistors, capacitors and the like, are formed on a single chip area. In addition to the large number of transistor elements, a plurality of passive circuit elements, such as capacitors, resistors and the like, are typically formed in integrated circuits that are used for a plurality of purposes, such as for decoupling.
For a variety of reasons, the various circuit portions may have significantly different performance capabilities, for instance with respect to useful lifetime, reliability and the like. For example, the operating speed of a digital circuit portion, such as a CPU core and the like, may depend on the configuration of the individual transistor elements and also on the characteristics and performance of the metallization system coupled to the CPU core. Consequently, the combination of the various circuit portions in a single semiconductor device may result in a significantly different behavior with respect to performance and reliability. Variations in the overall manufacturing process flow may also contribute to further variations in the performance capabilities between various circuit portions. For these reasons, in complex integrated circuits, frequently additional mechanisms are used so as to allow the circuit itself to adapt or change the performance of certain circuit portions to comply with the performance characteristics of other circuit portions. Such mechanisms are typically used after completing the manufacturing process and/or during use of the semiconductor device. For example, when certain critical circuit portions no longer comply with corresponding device performance criteria, adjustments may be made, such as re-adjusting an internal voltage supply, re-adjusting the overall circuit speed and the like, to correct such underperformance.
In integrated circuits, electronic fuses, commonly referred to as “e-fuses,” are used to facilitate the dynamic, real-time reprogramming of computer chips. Speaking abstractly, computer logic is generally “hard-coded” onto a silicon chip and cannot be changed after the chip has been manufactured. By utilizing one or more e-fuses, a chip manufacturer can change some aspects of the circuits on a chip. If a certain sub-system fails, is taking too long to respond, or is consuming too much power, the chip can instantly change its behavior by “programming” an e-fuse. Programming of an e-fuse is typically accomplished by forcing a large electrical current through the e-fuse. This high current is intended to break or rupture a portion of the e-fuse structure, which results in an “open” electrical path, and changes the circuit routing. Fuses are frequently used in integrated circuits to program (or make a selection between) redundant elements or to effectively replace defective elements with an identical functional element. Further, e-fuses can be used to store die identification or other information, or to adjust the speed of a circuit by adjusting the resistance of the current path. Device manufacturers are under constant pressure to produce integrated circuit products with increased performance and lower power consumption relative to previous device generations. This drive applies to the manufacture and use of e-fuses as well.
As noted above, programming an e-fuse generally involves passing a current though the e-fuse of sufficient magnitude such that, due to resistance heating, some portion or component of the e-fuse ruptures, thereby creating an open electrical circuit. After programming the e-fuse, the ruptured portion should be substantially uniform across its width. Any significant non-uniformities can result in incomplete programming, causing faults or improper operation.
The present disclosure is directed to various methods of making an e-fuse for use on integrated circuit products and the resulting integrated circuit product.